In a previous study we demonstrated that inhalant use is a good vulnerability marker for injecting drug use. The study was based on the National Household Survey on Drug Abuse. The major restriction of our findings were that the analyses were based on a survey with cross-sectional character. As a follow-up to that study, we are currently analyzing data from a recently completed longitudinal study. A cohort of African American school children have been followed from first grade to tenth grade. Sixteen years later 82% of those children, now approximately 32 years of age, have been re-interviewed. These follow-up data allow us to test our hypothesize that those who used inhalants during their youth are at a greater risk for use of heroin, allowing for a clear evaluation of time sequence. After elimination of those respondents who used heroin as adolescents and those with missing responses, we were left with 698 respondents. Preliminary analyses indicate that after adjustment for sociodemographic factors and adjustment for use of marijuana, inhalant use was a significant predictor of later heroin use (RR: 7.6, 95% CI: 1.73-33.27). In the same model we found use of marijuana also to be a predictor with a slightly lower point estimate of RR = 5.4 (95% CI of 1.84-15.85). None of the sociodemographic factors was significantly associated with later heroin use. These findings strengthen our argument that early inhalant use deserves more attention, not only because of toxicity associated with long and short term exposure, but also as a vulnerability marker for increased risk of injected drugs such as heroin.